Assessment of Spatial Distribution of Water Discharge from the Kaliningrad Lagoon and the Pregolya River (the Baltic Sea) Based on Satellite Monitoring

In the context of high anthropogenic pressure and eutrophication of the waters in the southeastern Baltic Sea, it is important to monitor the plume of highly productive waters from the Kaliningrad Lagoon through the Baltic Strait. Seasonal and interannual variability in plume propagation was estimated using satellite data from January 2020 to October 2024, and was then compared with expeditionary salinity measurements. The plume area was largest during the flood period (February–March) and the summer period (June–July), when strong winds contributing to plume dissipation were absent. Analysis of wind conditions and plume movement direction showed that, in most cases, the plume propagates along the coast to the northeast towards Cape Taran, predominantly in response to southwest and southeast winds. In autumn, dominant westerly winds press the plume to the coast. The hydrophysical structure of the plume corroborates the findings derived from satellite data.